Roll bumper stabilizer bar links

ABSTRACT

A vehicle suspension is provided that includes a frame supporting a pair of laterally spaced apart suspension members pivotally supported on the frame and movable in a vertical direction. A pair of wheel ends is each supported respectively on one of the suspension members. A stabilizer bar is supported on the frame laterally between the suspension members. The stabilizer bar includes opposing ends each respectively proximate to one of the suspension members. A pair of resilient stabilizer bar links each respectively interconnect one of the ends and one of the suspension members and transmit torsional force to the stabilizer bar in response to movement of the suspension members in the vertical direction during roll conditions. The links have first and second deflection rates during the roll condition with the first rate being less than the second deflection rate. The links transition from the first deflection rate to the second deflection rate and from the second deflection rate to an effective zero deflection rate.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a stabilizer bar for a vehicle suspension system, and more particularly, the invention relates to stabilizer bar links used to attach the ends of the stabilizer bar to a vehicle suspension member.

[0002] Stabilizer bars are used in vehicle suspension systems to stabilize the vehicle laterally during vehicle turning and maneuvers in which the vehicle rolls side to side. In addition to stabilizing the vehicle, the stabilizer bar provides feedback to the vehicle operator regarding the stability of the vehicle during the turning maneuver. Providing a soft feel in which the vehicle rolls appreciatively during a turning maneuver, the driver is made aware of the vehicle's instability thereby encouraging the driver to operate the vehicle more conservatively to prevent loss of control of the vehicle during the turning maneuver. By way of contrast, a firm or hard vehicle provides the vehicle operator with feedback that the vehicle is stable by rolling very little during the turning maneuver. In this manner, the vehicle operator may drive more aggressively than desired causing the vehicle to suddenly lose traction and spin out of control.

[0003] The roll feel provided by the suspension assembly is determined by the stiffness of the suspension springs, the stiffness of the stabilizer bar itself, and the stiffness of the bushings used in the connections of the stabilizer bars and suspension members such as lower control arms. The roll stiffness is typically selected to provide either a soft feel or a firm or hard feel depending upon the particular vehicle application and expectation of the driver. It would be desirable to provide a variable roll stiffness and feedback to the driver during various roll conditions.

SUMMARY OF THE INVENTION AND ADVANTAGES

[0004] The present invention provides a vehicle suspension including a frame supporting a pair of laterally spaced apart suspension members pivotally supported on the frame and movable in a vertical direction. A pair of wheel ends is each supported respectively on one of the suspension members. A stabilizer bar is supported on the frame laterally between the suspension members. The stabilizer bar includes opposing ends each respectively proximate to one of the suspension members. A pair of resilient stabilizer bar links each respectively interconnect one of the ends and one of the suspension members and transmit torsional force to the stabilizer bar in response to movement of the suspension members in the vertical direction during roll conditions. The links have first and second deflection rates during the roll condition with the first rate being less than the second deflection rate. The links transition from the first deflection rate to the second deflection rate and from the second deflection rate to an effective zero deflection rate.

[0005] Accordingly, the above invention provides a variable roll stiffness and feedback to the driver during various roll conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Other advantages of the present invention can be understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

[0007]FIG. 1 is a perspective view of a vehicle suspension system;

[0008]FIG. 2 is a chart depicting the link deflection versus roll input for the present invention stabilizer bar links;

[0009]FIG. 3 is a stabilizer bar link having a bushing with a variable deflection rate;

[0010]FIG. 4 is an alternative bushing;

[0011]FIG. 5 is another stabilizer bar link of the present invention;

[0012]FIG. 6 is yet another stabilizer bar link of the present invention;

[0013]FIG. 7 is still another stabilizer bar link of the present invention; and

[0014]FIG. 8 is yet another stabilizer bar link of the present invention having active control.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] A vehicle suspension system 10 is shown in FIG. 1. The system 10 includes a frame 12 that supports the lower control arm 14 and an upper control arm 16. A knuckle 18 is secured between the lower 14 and upper 16 control arms. A spring 20 may be arranged between the lower control arm 14 and the frame 12. Wheel ends 22 are supported by the knuckles 18. Although a four-bar suspension arrangement is shown, it is to be understood that the present invention may be utilized with any suspension arrangement.

[0016] A stabilizer bar 24 is arranged laterally between the suspension members on either side of the vehicle. The stabilizer bar 24 includes a lateral bar portion 25 supported on the frame 12 by brackets 26. The stabilizer bar 24 also includes arms 28 that are secured to the lower suspension arms 14 by stabilizer bar links 30. The stabilizer bar links 30 transmit the vertical inputs from the suspension members to the stabilizer bar 24 to realize stability to a vehicle during roll conditions and provide feedback to the vehicle operator indicative of the vehicle stability. The present invention provides a roll curve shown in FIG. 2 that provides at least a soft feel (shown by curve A), a firm feel (shown by curve B), and a hard feel (shown by curve C).

[0017] The stabilizer bar link 30 includes first 32 and second 34 ends defining first 36 and second 38 connections. Each of the connections may include first 40 and second 42 resilient members that are coaxial with one another that define a bushing. The bushing includes a hole 44 for receiving a fastener that attaches the stabilizer bar link between the suspension member and the stabilizer bar. The resilient members 40 and 42 may be made out of a rubber material. The first resilient member may be softer than the second resilient member 42 such that the first member 40 deflects greater than the second member 42. In this manner, the first resilient member 40 will begin deflecting first and provide a soft feel. The second resilient member 42 will then begin to deflect after the first member 40 has deflected and provide a firmer feel. Finally, the resilient members 40 and 42 will no longer deflect and provide a effectively zero deflection rate which provides a hard feel to the vehicle operator.

[0018] The bushing 46 shown in FIG. 4 may also be used with the link 30 to provide a variable deflection rate. For example, the bushing includes arcuate apertures 48 arranged about the hole 44. The bushing 46 will deflect until the arcuate apertures 48 become closed and the inner portion of the hole 44 engages the outer portion of the bushing 46 to provide a firm feel. The bushing 46 will cease deflecting and provide a hard feel to the vehicle operator.

[0019] Another stabilizer bar link arrangement is shown in FIG. 5. The stabilizer bar link 30 includes a link 50 having flanges 52. Resilient members 54 are arranged about the suspension member 14 and the stabilizer bar 24 to effectively sandwich the suspension member and bar between the flanges 52. The fasteners 56 such as nuts are secured to the link 50 to connect the stabilizer bar 24 to the suspension member 14. The resilient members 54 adjacent to the suspension member 14 and stabilizer bar 24 may have a first deflection rate, and the resilient members 54 adjacent to the flanges 52 may have a second deflection rate different than the first deflection rate.

[0020] Another stabilizer bar link arrangement is shown in FIG. 6. The link 30 may include a rigid member 58 telescopically received within a housing 60. The housing 60 may be secured to the stabilizer bar 24 and the rigid member 58 may be secured to the suspension member 14. First 62 and second 64 resilient members may be coaxially arranged relative to one another. The resilient members 62 and 64 may be secured to one another and secured between the rigid member 58 and the housing 60. The first resilient member 62 has a first deflection rate, and the second resilient member 64 has a second deflection rate different than the first resilient member 62. The housing 60 may include a stop 65 to limit the motion of the rigid member 58 to the housing 60.

[0021] The first stabilizer links are shown in FIGS. 7 and 8. Referring to FIG. 7, the link 30 may include a housing 66 having a piston 68 disposed therein. A rod 70 is secured to the piston 68 and may be attached to the lower suspension member 14. The housing 66 may be attached to the stabilizer bar 24. The housing 66 defines a fluid cavity 72 that is separated into first 74 and second 76 chambers by the piston 68. The housing 66 is filled with hydraulic fluid. An orifice 78 may be arranged in the piston to define a damping rate that corresponds to a first deflection rate. First 80 and second 82 springs may be respectively arranged within the first 74 and second 76 chambers. The springs 80 and 82 define a second deflection rate.

[0022] Referring to FIG. 8, a magneto-rheological fluid stabilizer bar link 30 is shown. The link 30 includes a housing 84 having a piston 86 disposed therein with a rod 88 connected to the piston. The housing 84 and rod 88 are connected between the suspension member 14 and the stabilizer bar 24. The housing 84 defines a fluid cavity 90 separated into first 92 and second 94 chambers by the piston 86. The piston 86 may include an orifice 96 for providing damping. A coil 87 may be arranged about the housing 84 and is connected to a controller 98. The controller 98 energizes the coil 97 and creates a magnetic field about the housing 84 to change the viscosity of the magneto-rheological fluid thereby changing the fluid flow through the orifice 96. Accelerometers 100 and 102 are connected to the controller and provide lateral and forward/rearward acceleration. The controller 98 is programmed to selectively control the magnetic field produced by the coil 97 in response to the accelerometers 100 and 102 to provide variable roll damping. In this manner an infinitely variable damping or deflection rate may be provided by the stabilizer bar link 30.

[0023] The invention has been described in an illustrative manner, and it is to be understood that the terminology that has been used is intended to be in the nature of words of description rather than of limitation. Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described. 

What is claimed is:
 1. A vehicle suspension system comprising: a frame; a pair of laterally spaced apart suspension members pivotally supported on said frame and movable in a vertical direction; a pair of wheel ends with each wheel end supported each respectively on one of said suspension members; a stabilizer bar supported on said frame laterally between said suspension members, said stabilizer bar including opposing ends each respectively proximate to one of said suspension members; and a pair of resilient stabilizer bar links each respectively interconnecting one of said ends and one of said suspension members and transmitting a torsional force to said stabilizer bar in response to movement of said suspension members in said vertical direction during a roll condition, said links having first and second deflection rates during said roll condition with said first deflection rate less than said second deflection rate, and said links transitioning from said first deflection rate to said second deflection rate and from said second deflection rate to an effective zero deflection rate.
 2. The vehicle suspension system according to claim 1, wherein said stabilizer bar link includes opposing link ends with one of said link ends secured to said stabilizer bar end at a first connection and the other of said link ends secured to said suspension member at a second connection.
 3. The vehicle suspension system according to claim 2, wherein said stabilizer bar link includes first and second resilient members respectively providing said first and second deflection rates.
 4. The vehicle suspension system according to claim 3, wherein said first and second connections each include a bushing having a hole adapted to receive a connection member, said bushing defined by said first and second resilient members arranged coaxial with one another about said hole.
 5. The vehicle suspension system according to claim 3, wherein first and second resilient members are arranged adjacent to one another on each side of suspension member and each side of said stabilizer bar.
 6. The vehicle suspension system according to claim 2, wherein said first and second connections each include a bushing having a hole adapted to receive a connection member, said bushing having at least one aperture arranged about said hole.
 7. The vehicle suspension system according to claim 6, wherein said bushing includes spaced apart arcuate apertures about said hole.
 8. The vehicle suspension system according to claim 3, wherein one of said connections is provided by a rigid member telescopically received in a housing and movable axially relative thereto with said first resilient member arranged about said rigid member and said second resilient member arranged about said first resilient member, said resilient members interconnecting said rigid member to said housing.
 9. The vehicle suspension system according to claim 1, wherein said stabilizer bar link includes opposing link ends with one of said link ends secured to said stabilizer bar end and the other of said link ends secured to said suspension member, stabilizer bar link includes a housing connected to one of said link end and defining a fluid cavity with a piston disposed in said cavity and connected to the other of said link ends, said piston separating said cavity into first and second chambers with said member including an orifice fluidly connecting said first and second chambers.
 10. The vehicle suspension system according to claim 9, wherein first and second springs are respectively disposed within said first and second chambers and cooperating with said piston
 11. The vehicle suspension system according to claim 10, wherein said cavity is filled with hydraulic fluid.
 12. The vehicle suspension system according to claim 9, wherein said cavity is filled with magneto-rheological fluid.
 13. The vehicle suspension system according to claim 12, wherein a controller is connected to a magnetic source cooperating with said magneto-rheological fluid, said controller commanding said magnetic source generating a change in viscosity of said fluid to provide said first and second deflection rates.
 14. The vehicle suspension system according to claim 13, wherein an accelerometer is connected to said controller providing vehicle rate of roll to said controller.
 15. A method of providing driver feedback during vehicle roll maneuvers comprising the steps of: a) providing a stabilizer bar attached to suspension members by stabilizer bar links; b) rolling the vehicle at a first stabilizer bar link deflection rate providing a soft feel to the driver; c) rolling the vehicle at a second stabilizer bar link deflection rate providing a firm feel to the driver; and d) rolling the vehicle at an effective zero deflection rate providing a hard feel to the driver.
 16. The method according to claim 15, wherein the deflection rates of steps b)-d) are provided a single stabilizer bar link.
 17. The method according to claim 16, wherein the stabilizer bar link includes at least one elastomeric member providing the deflections rates.
 18. The method according to claim 16, wherein the stabilizer bar links includes a piston and cylinder arrangement. 